Radio-over-fiber (RoF) refers to a technology whereby light is modulated by a radio signal and transmitted over an optical fiber link to a remote antenna unit for facilitating wireless access. In a conventional ROF network, an optical transmitter converts radio signals into optical signals and transmits the optical signals through the optical fibers. At the other end of the optical fibers, an optical receiver is provided to convert the optical signals into radio signals. The drawbacks of the conventional remote antenna unit are as follows.                1. Complexity of remote antenna unit (RAU): Complexity of RAU leads to increase in cost and power usage.        2. Capacity of optical fiber is not fully utilised: The conventional system does not utilise all bandwidth of the optical fiber as it uses separate fiber or different wavelength in uplink and downlink data transmission.        3. Different fiber cables for downlink and uplink transmission: in practise, separate fibers or different wavelength are used for downlink and uplink to avoid interference. However, this also leads to increase in cost and power usage.        4. Signal collision: When multiple services are transmitting in a single system, there are possibilities that the signals will collide or interfere with each other.        
Therefore, a need exists for the RAU to be designed with reduced components and less complexity due to multiple numbers of to be deployed at the residential or commercial area. The invention provides an economical and effective RAU system that implements a reuse carrier technique for full-duplex data transmission.